Chances are you'll be doing a lot more tracking. Blunt tips are for very small game, intended to knock they prey out cold or cause death by blunt trauma.
Hunting tips are intended to increase depth of penetration as well as doing continuous damage to the vital organs once full penetration has occurred.
Hunting tips will almost always penetrate deeper than field tips in flesh, because the razor cut a cross around the puncture, this reduces the tension of the wound around the shaft. In other words, A field tip will stop faster because the flesh will be grabbing it better.
Can you use field tips to hunt? Sure, but you will likely be forced to track for longer, the arrow may fall out of the wound when the animal is running through brush, and may be able to find a spot to hide and die (or heal) and you may never find it.